Insulating covering



'April 6,1943. A. D. M NUTT INSULATING COVERING 2 Sheets-Sheet 1 FiledDec. 5; 1936 INVENTOR TTORNEY Ap 6, 1943. A. D. M NUTT INSULATINGCOVERING Filed'Dec. 5, 1936 2 Sheets-Sheet 2 INVENTOR Aeflme Aha 5MCZVl/TZ' Patented Apr. 6, 1943 to Certain-Teed York, N. I, acorporation of Products Corporation, New Maryland Application December5, 1938, semi No. 114,359

20 Claims.

This invention relates to felts and similar fabrics composed of fibrousmaterials. The invention especially relates to fibers of mineral origin,and more particularLv to fibers of rock or vitreous origin. 7

By processes which in themselves form no part of the present invention,mineral materials in the form of fibers have been manufactured.-

from rocks of various kinds such as limestone,

dolomite, shale, and mixtures of such rocks, from slag, glass, and othersiliceous or vitrifiable materials. The term mineral wool" is generallyunderstood to designate fibers of this character of which specificexamples are glass wool, slag wool and rock wool. Fibers obtained bythese processes may be of difierent degrees of, fineness and of length,and various grades and qualities may be obtained with respect not onlyto the fineness and length of fiber but also with respect to theadmixture of non-fibrous particles or other foreign materials.

Such mineral wools are commonly used for insulating purposes in mass orbulk. For example masses of such mineral wool may be placed betweenstuds-in partitions for the purpose of providing the desired air cellswhich, as is well known, aflord themost eifective insulation. Suchmaterials in bulk or mass also are known to have valuable acousticalinsulating properties.

The present invention proposes the formation; of a sheet of mineral woolfibers which may be suitable for various purposes for which felted'thefiber web or for the felted in the felting process as do celluloseor similar common fibers used in ordinary felts. Nevertheless bysuitable modification of the ordinary felting or paper making process,for example by providing'an apron or other suitable support for sheetduring its travel through the machine or upon'delivery to a subsequentoperation or treatment, such as the saturating" operation in roofingmanufacture, a felt composed of mineral wool fibers may be prepared andmay be handled and treated in the same manufacturing operation asordinary felts.

To secure a web of sufiicient strength to be handled it may also beadvantageous to admix with themineral wool fibers in the process ofpreparing the fiber for the felting machine or at the point of deliveryto the felting machine a certain amount of organic. fibers, such ascellulose fibers or wool fibers, or of natural mineral fibers, such asasbestos. Such an amount of the auxiliary fibrous material is utilizedas will not interfere with the advantages gained by the use of mineralwool fibers in a felted sheet, and for the purposes of the inventionpreferably the felted sheet contains fibers of mineral wool inpredominant amount, in order tosecure the open construction which ischaracteristic of such sheets of various animal and vegetable fibers arenow used, particularly for the purpose of providing a base felt, as asubstitute for rag felt and for felts of wood fiber or for other feltedbase materials ordinarily used in the roofing industry.

- According to my invention I propose to prepare a mixture with or asuspension in water of mineral wool, corresponding to the stock preparedin the manufacture of ordinary papers and felts of cellulose or otherfiber. I have found that such stock maybe felted as'in the ordinarypaper or felt making process. By selection of the proper kind of mineralwool a sheet of the felted fibers may be made from this suspension whichwill be sufficiently strong to be self-supporting in the felt makingprocess. It also may be so formed as to be adaptable for furthertreatment in various v processes to which ordinary felts are commonlysubjected, including facture.

processes in roofing manu- Possibly because of their smooth or glassysurface and their straightn'ess I have found that mineral wool fibers donot form as strong a web 1 less complet mineral wool fibers in bulk andby which are secured the heat and sound insulating qualities.

By thus forming a felted sheet having an open construction it becomespossible to manufacture weatherproof protective materials, such as sheetroofing, by impregnating the felted sheet of mineral wool fibers with awaterproofing material, such as asphalt or other bituminous impregnatingmaterial, in a manner similar to that now practiced in the impregnationvof rag felt or other cellulose base sheets in the roofing 'art. Whileordinarily in the roofing art the rag or other felt is first impregnatedthroughout with a saturant such as asphalt, within the scope of myinvention I include not only the more or impregnation or saturation ofthe mineral wool felted sheet, so that the sheet carries as much of thesaturant as possible in accordance with regular roofing practice, but Ialso intend that the sheet of mineral wool felt of my invention for somepurposes may be partially saturated substantially uniformly throughfibers and to secure a lighter sheet. for a given thickness. As has beenstated above, in the felted sheet the open character of the structurewhich exists in masses of such mineral wool fibers in bulk may beretained to a substantial degree.

It is a feature of my invention, therefore, that I obtainnot only aweatherproof and water resisting covering material but one whichcombines with these qualities the characteristics of heat and soundinsulation. Such a sheet also, because of the presence therein of theinert noncombusti'ble mineral fiber, is more fire resistant .and lesssubject to rot and to attack byvermin than ordinary felted sheetscomposed largely or entirely of organic fiber. Especially in fibroussheets used as bases [for roofing materials the increased resistance tofire obtained by eliminating the saturant, and having thereon a coatingof adhesive usually of bituminousmaterial such as asphalt. Such asaturated and coated sheet would correspond to the so called smoothsurfaced roofing especially if, as in common practice, a light surfacingof talc or mica is applied to the adhesive coating. If desired on theother hand, there may be applied to this coating, as in the case ofordinary surfaced roofing, a surfacing of granular material, such asslate, or ceramic, fired or painted granules. Thus the inventionprovides substantially for the substitution of a base sheet of mineralfibers, especially of the class known as "mineral wool," (for the ragfelt or cellulose felt base sheets ofordinary roofing. The variousmodifications and manipulations as practiced in the roofing industry tosecure different roofing products, such as shingles or siding elements,may be carried out with the roofing material of the invention as withthe ordinary roofing sheets.

As a further application of the invention I propose the formation ofsheet material, for pur-. poses for which ordinary roofing is'used, byapplying to a base sheet of felted mineral wool fibers a coating ofadhesive, such as asphalt, said base sheet being without theimpregnation of the "saturant as in ordinary roofing. Said coatingadhering to one surface of the felted sheet may be of such character andthickness as to serve as the waterproofing and weather resisting layerand, if desired, this layer may bind upon the felt a surfacing layer ofgranular material, :as in slate surfaced roofing or a surfacing layer ofmica, talc or fine sand as in "smooth surfaced roofing. On the underfaceof said felted but unimpregnated sheet a sealing or backing coating maybe applied if desired, as in ordinary roofing practice.

In one application of my invention, in order to secure the advantagethereof in connection with ordinary roofing sheets which utilize a feltbase of organic fiber, such as rag felt or cellulose fiber felts, Ipropose to apply to the back of the ordinary roofing sheet a layer ofmineral wool fibers. By means of such a layer may be secured in anordinary roofing product the desired heat and sound insulating qualitiesas well as improved resistance to fire. The thickness of this layer maybe made greater or less to secure greater or less effect of suchinsulation and resistance within the required limits of cost ofmanufacture. Broadly within the scope of my invention, 5

this layer of mineral wool fibers may be applied to the back of theroofing sheet in any desired manner. For example, such a, layer may beformed by dropping the fibers on the back side of the roofing sheet,after it has left the coating bath, by first passing the sheet over areversing roll. If necessary or desirable, after the loose mineral woolhas been dropped on or otherwise brought into contact with the back sideof the sheet and adheres to the still adhesive coating thereon, it maybe pressed by passing the sheet through pressing rolls to securepermanent attachment tothe sheet.

Preferably, however, I apply the layer of mineral wool fibers in theform of a felted sheet of said mineral wool fibers which may be fedparallel tothe feeding of the roofing sheet and may be brought intocontact with said roofing sheet directly after it leaves the coatingbath which,

in the ordinary roofing process, applies asphalt ordinary roofing sheet,and avoid the necessity of markedly altering the ordinary process ofproducing such a roofing sheet, while at the same time securing theinsulating quality afforded by thelayer of applied mineral wool fibers.In addition, shingle or siding elements or units may be produced whichhave the virtue of thick butt appearance because of their thickness dueto the lamination added to the ordinary sheet and which are made of lowweight per unit area. If desired on the other hand, the total thicknessof the laminated sheet or the total weight of the sheet per. unit areamay bemade the same as that of ordinary roofing.

The waterproofing-capacity of the sheet may be maintained by utilizingthe same character and thickness of coating upon the face thereof as inordinary roofing. In such a laminated product the base sheet. of rag orcellulose fiber, if desired, may be made lighter than in ordinaryroofing and the insulating quality, thick butt ap pearance, fireresistance, etc., may be secured by the lamination of the mineral woolfiber sheet. Also within the scope of my invention the base sheet itselfmay be of mineral wool fiber, felted and impregnated as described above,said roofing product so formed having laminated .thereto on theunderside thereof a felted sheet of mineral wool fiber which is notimpregnated, in order to secure the insulating and other qualities.

As will be more particularly described in connection wi h the drawings,the lamination or backing sheet of mineral wool fiber' may be applied tothe roofing sheet in such a way as to cover only a part of the area ofthe roofing sheet. This partial coverage may be so placed ,that themineral woolbacking underlies, in shingle or roofing elements cut fromthe sheet, that portion thereof which is to be exposed in the assemblyof the elements in a roof or a covering construction. In some cases,however, it may be preferable to apply the mineral wool lamination so asto form a backing upon that portion of the element which is to beoverlapped by a superimposed element. In some cases also the whole ofthe element may be backed by sucha lamination. In the last two instancesit will be clear that that portion of the element which is next to thesupporti g structure will have the mineral wool laminati n adjacent toor in contact with said structure. In some cases this may afi'ord bettersound and insulating qualities. The lamination also may be applied uponthe upper surface of the element upon that portion thereof which isoverlapped by a superimposed course.

In some cases or with some types of mineral wool fibers instead of, orif necessary or desirable,

in addition to the admixture of auxiliary fibers, suchas cellulose orother organic fibers or of asbestos for the purpose of increasing thestrength of the felted web during the felting process or thereafter, Imay incorporate, either in the preparatory process or at the deliveryend of the felting machine, a binder or sizing material; such assilicate of soda, latex, casein, emulsified asphalt or other materials,which will not interfere with the felting process and which will be ofassistance in holding the fibers together until the felting is completeand also thereafter during mechanical handling of the sheet. Suchbinders or sizing materials may be used in such quantity as to beeffective for the purpose without interfering with the open structure ofthe felted mineral wool which is a feature of the present invention anduseful for the purposeof securing light weight and sound and heatinsulation and fire resistance.

In some cases it may be desirable to form in the felting machine, suchas a paper machine, a felted web having two or more laminations whichlaminations may be felted together in the felting process or may beadhesively bound to gether by a suitable adhesive or sizing materialsuch as is mentioned above. 'Moreover, within the scope of theinvention, the composition of the twolaminations may be different, onebeing so formed in'the preparatory process that it will felt to form arelatively strong sheet'but one capable of being saturated in the mannerof ordinary roofing felts, and the other with more open structureproviding good insulating quality, As an example of such a laminatedsheet may be mentioned a sheet or web of felted mineral wool fibersbound to or carried by a web of felted cellulose fibers or to a sheet ofrag felt. For the carrying web of cellulose fibers may be substituted,however, a web of mineral. wool fibers felted or prepared, as describedabove, so

as to provide the desired strength and, as well, the capacity forsaturation with asphalt or similar saturant.

The invention will be further described inconnection with the drawingsinwhich Fig. 1 represents a back view of a shingle strip embodying theinvention.

Fig. 2 is a section on line 2--2 of Fig. 1.

Fig. 3 shows in section an assembly of the shingle strips of Fig. 1.

Fig, 4 is an individual shingle showing a modified embodiment of theinvention.

Fig. 5 shows in section an assembly of the elements of Fig. 4.

Fig. 6 shows in section a further bodiment of the invention.

Fig. 7 shows a section similar to Fig. 2 but of modified em modifiedform.

Fig. 8 shows a cross-section of a tank for carrying out the process ofthe invention.

In Fig. 1 the element i is in the form of a shingle strip havingcut-outs 3 between tabs 4 and this figure shows a view of the under sideof such a shingle having applied to the tab portions assembly of suchelements.

thereof a layer I of felt of mineral wool of the type described above.Such a shingle, as may beseen from Fig. 2 consists of a base 8 of saturated felt, as in ordinary roofing. having thereon a coating I providingthe weather resisting layer and serving to bind to itself and theshingle a surfacing layer Ill upon the outer face of the tabs 4 in the'usual manner. Upon the underside of the shingle is applied a seal orbacking coating H of asphalt. Laminated to the shingle upon theunderside thereof, either by the adhesive action of the coating II or byapplied adhesive or by other suitable means, is

shingle, this shingle being raised from the underlying shingle becauseof the intervening felt layer, and the overlapped portion of saidunderlying shingle is closed off. While this is the preferableconstruction with shingles of the type shown in Figs. 1 and 2. anydesired portion of the tab may be covered. For example, the portion ofthe tab adjacent to the edge 5 thereof only may have applied thereto thefelt lamination so as to raise the edge of the shingle and present agreater thickness thereof in the assembly. On the other hand, ifdesired, the entire underside of the shingle I may be covered by thefelt lamination, as shown in Figure 7. When the tab portion, in themanner illustrated in Fig. 1, is covered with the felt lamination notonly is a thicker butt end secured but the upper edge 1 of the shingleand the overlapped portion thereof, for the most part, are left in theordinary thickness and thus in the assembly of overlapping elements orshingles the effect of tapered shingle is secured in the roof as may beseen from Fig. 3.

In Fig. 4 is shown as a modification of the invention a backview of aroofing element of the type known as an "Individual shingle. In theelement l5 of Fig. 4 the lower portion l6 thereof represents the partwhich is to be exposed in the overlapping arrangement in an At the upperpart I! ofthe element is provided an offset i8 which acts as a spacingmeans in order that shingles laid adjacent in a course may becomepositioned in the course with the portions l5 thereof sepa rated in themanner of ordinary wood shingles. Upon the upper portion ll of shinglei5 is applied a backing layer or lamination 20. This layer, as describedin connection with Fig. 1, may be applied to the shingle i5 by causingit to adhere to the coating carried by the base of the shingle or byother means. Fig. 4 also may nation 20 being applied upon the undersideof the shingle, such shingles may be assembled in overlappingarrangement in the manner illustrated in'Flg. 5. The felt laminationsare then exposed upon the underside of the assembly of shingles and maybe in contact with the sup porting structure. For some purposes, such assound absorption, this may be a preferable COD. struction. It also willbe understood that if Fig. 4 is taken to represent the upper side of theshingle, the lamination 2. then representing a lamination applied to theupper face, this lamination in the assembly of elements would becomesandwiched between two shingles or elements in.

the overlapping arrangement. For some purposes, such as the preventionof conduction of transverse to the coursewise dimension of the shingleor covering elements such that the laminating layers of felt will be inoverlapped relation in the different courses or may only extendsubstantially to a common meeting line as illustrated in Fig. 5. Anysuch variations in the dimensions of the applied laminations come withinthe scope of the invention by which is secured the above describedadvantages of the open structure of the mineral wool felt lamination.

As.v shown in Fig. 6 in addition to the layer ID of granular materialbound upon the base a by the coating 9, by processes well known in theart a second layer of surfacing material may be bound upon the portionto be exposed of the element or shingle by a second layer 21 of asphaltor other adhesive coating; The layer 25 and the coating 21 may extendover the edge of the shingle to cover the surface of said edge which istransverse to the exposed face of'the shingle. The asphalt coating 21thus may seal the transverse edge surface of the shingle and may extendsomewhat around upon the underside of the mineral wool felt lamination 8applied to the underside of the shingle. Thus not only is the edgesurface of the ordinary shingle sealed in the manner in which it hasbeen heretofore accomplished but the ed e of the applied lamination ofmineral wool felt also is sealed and in addition such a marginal portionof the underface of said felt lamination as will prevent the absorptionof moisture and water by said felt lamination as it lies in contact withthe shingle of a subiacent course. The sealed edge surfaces. therefore,and particularly from the standpoint of the invention, the edge surfaceof the laminating layer not only are capable of resisting the absorptionof moisture and the action of the weather but the thick butt appearanceis enhanced by the extra coating layer and the surfacing layer andparticularly by that portion of these layers which extend around uponthe underface of the felt lamination.

While the invention has been described in its embodiment which utilizesmineral wool in connection with ordinary roofing materials and shingleor siding elements, and particularly mineral wool fibers in felted sheetform as applied or laminating layers upon said ordinary roofing sheetsand elements, this phase of the invention is not limited to layers orlaminations of mineral wool fibers. Within the scope of the invention isincluded the application of common fibers of organic origin, usuallyvegetable or animal fibers. as a layer or lamination upon the ordinaryroofing sheet or the shingle or siding element. These layers orlaminations may be applied in the various positions and relations uponthe shingle or siding elements which have been typically illustrated anddescribed above. While woven fabric layers, more particularly ofvegetable fibers have been used as backing sheets for felted andsaturated weather-resisting sheets, I am not aware that heretofore ithas been proposed to apply to a weather-resisting sheet. such as a sheetof roofing, a layer of fibers applied so as to provide in the layer anopen arrangement of the fibers so as to be capable of affording heat orsound insulation or capable of adding to the fire-resisting capacity ofthe weatherresisting sheet.

In order to prevent rotting of such organic fibers or other-deterioration thereof or attack by vermin, preferably such organicfibers are treated with preservatives or germicides such as creosote,bichloride of mercury, or in some cases with asphaltic or bituminousmaterials. In all cases, however, to accomplish the purpose of theinvention such treatment is so carried out that the fibers as they areapplied to-the roofing material may be left with an open structure ofthe layer or lamination and preferably as a felted layer or lamination.

In the claims the words "dry felt" or "d y web" have been used todesignate a web or layer of fibers which is not thoroughly impregnatedwith a saturant, such as asphalt. Although such a "dry" felt or layermay, as described above, have certain sizing or binding materialstherein to increase the strength of the layer or web, nevertheless theterm "d y" is intended to indicate a fibrous layer or felted web inwhich the open structure thereof is substantially that which would beobtained without such sizing or binding materials. While a "saturatedweb may. as in ordinary roofing practice, be capable of absorbing wateror other liquid less viscous than asphalt or similar saturants, thedegree of openness of the structure of such a saturated layer of fibersor felted web is markedly reduced with respect to a layer or web whichmay be designated as a "dry layer or web.

I In order to apply the coating 21 upon shingles of the form shown inFigure 6 described above, I propose a method which will insure theapplication of this coating upon the face of the shingle which is to beexposed upon the roof. but will prevent the application of the coatingto the mineral wool lamination 6 applied to the underside of theshingle. This method comprises the step of placing two shingles ofsimilar dimension with the lamination 6 in contact with each other, thatis with the shingles back to back. This leaves the surfaces of theshingles to which the coating 21 is to be applied exposed upon thisassembly of two shingles, so that this assembly may be dipped in a bathof asphalt in the manner illustrated in Figure 8 in which is. shown atank 30 containing the bath 32 of asphalt or other coating material.Supported by suitable means attached to the walls of the tank 30 so asto be submerged in the bath of asphalt is a shelf 34 upon which theedges of the pair of shingles may rest as they are dipped together intothe bath. The level of the bath of asphalt may be kept at such adistance above the upper surface of the shelf 34 that the width of thecoating in the direction transverse to the lower edge of the shingle maybe de ermin d by bringing the lower edges of the pair of shingles intocontact with shelf 34.

In order to keep the shingles together so that the lower edges thereofdo not separate and permit the asphalt to run up between the twoshingles, clips 35 may be attached to'the shelf 84. These clips It maybe formed to bear against the shingles as they are set down upon theshelf 3|, thus maintaining the back faces of the shingles in contact.Application of the coating of-asphalt upon the mineral wool felt 8 thusis prevented. Nevertheless, the lower edges of both shingles are coated,including the lower edge of the mineral wool felt on both shingles. Assuch felt is quite absorbent by capillary action it will draw a slightamount of the asphalt up through the edge surface thereof but thecoating substantially remains applied to and covers both the lower-edgesof the shingles and the lower edges of the mineral wool felts and tendsto also cover only a narrow marginal portion of the back faces of thismineral wool felt 8, as illustrated in Figure 6.

Instead of. or in addition to, the clips 35 held by the shelf 34, I mayfasten the two shingles together by removable clips or by othermechanical means before dipping in the bath 32. I also may tack theseshingles together with adhesive applied at points along the matchededges of the two shingles. Such'means for holding the shingles togetherpreferably are easily removable and should be designed so as not todamage the shingle or interfere in any marked degree with theapplication of the asphalt coating 21 to the face or edges of the twoshingles.

As the object of placing th shingles back to back is to prevent theapplication of the asphalt coating on the mineral wool layer, I maysubstitute for one of the shingles, if desired, a plate of metal orother material against which a single shingle may be placed, held byclips or other means during the dipping in the bath 32. Also if desired,such a plate may be placed between the two shingles before dipping themin the bath. By the use of such apparatus, or by other means, theprocess of the invention may be carried out by which process shingles,having upon the underside thereof a lamination of fibrous material ofopen structure and, particularly, a layer of mineral wool felt, may beprovided with a water resisting coating on the face to be exposedthereof and upon the edge surfaces thereof, the edge surfaces of themineral wool felt and a marginal portion only of the back faces of themineral wool felt being coated with or absorbing asphalt while the backface substantially is left uncoated and unsaturated so that itsinsulating quality is maintained.

Having thus described the invention I now claim:

1. A web comprising mineral wool fibers felted to form a web having anopen structure to provide heat and sound insulating quality, and a webof mineral wool fibers laminated to said first web and having the fibersthereof felted to form a web with greater strength than said first weband capable of carrying a substantial amount being in the form of ofcourses of shingles in overlapping arrange thereof a dry lamination ofmineral wool fibers providing an open structure, said dry lamination adryweb of self-sustaining felted structure.

3. A roof construction comprising a plurality ment, and a dry layer ofmineral wool fibers providing an open structure, said layer being sopositioned on the shingles as to lie between the overlapped portions oftwo overlapping shingles, said dry layer being in the form of a dry webof self-sustaining felted structure.

4. A roofing sheet comprising a weather-resisting web having laminatedthereto a dry web of mineral wool fibres in the form of a selfsustainingfelted structure in said dry web.

5. A roofing sheet comprising a weather-resisting web having laminatedthereto a dry web of mineral wool fibres in the form of a waterlaidfelted structure in said dry web.

6. A roofing element comprising a weather-resisting web having laminatedthereto on the underside thereof a dry web of mineral wool fibres in theform of a self-sustaining felted structure in said dry web. 7. A roofingelement comprising a weatherresisting web having laminated thereto uponthe underside of the portion of the element to be exposed in an assemblyof elements in overlapping arrangement a dry web of mineral wool fibresin the form of a self-sustaining felted structure in said dry web.

8. A roofing element comprising a weatherresisting web having laminatedthereto upon the underside of the portion of the element which in anassembly of elements in overlapping arrangement is overlapped by asuperjacent element a dry web of mineral wool fibres in the form of aself-sustaining felted structure in said dry web.

9. A roofing element comprising a weatherresisting web having laminatedthereto upon the upper face of the portion thereof which is to beoverlapped by a superjacent element in an assembly of elements inoverlapping arrangment a dry web of mineral wool fibres in the form of aself-sustaining felted structure in said dry web.

10. A roofing sheet according to claim 4, said sheet having a sealingcoating covering the edge surface of said dry web which is transverse tothe face surface of the sheet.

of water repelling impregnating material, the

mineral wool: fibres of said web of greater strength being inpredominant amount and formed as a water-laid felted structure in theweb.

2. A roof "construction comprising a plurality 11. A roofing sheetaccording to claim 4, said sheet having a sealing coating covering theedge surface of said dry web transverse to the face of the sheet andalso covering a marginal portion only of the face surface of said dryweb opposite to that which is next to said weatherresisting web.

12. A shingle formed from a sheet as defined in claim 4 having in theportion thereof to be exposed in an assembly of shingles in overlappingarrangement cut-outs between tabs, said felted web extending above theinner end of the cutouts.

13. A roofing sheet comprising a web of felted fibrous materialimpregnated with a bituminous water-resisting saturant and carrying on aface. thereof a coating of bituminous material to form aweather-resisting base sheet, and a dry web of mineral wool fibres inthe form of a self-sustaim ing felted structure in said dry weblaminated to the opposite face of said base sheet and held thereto toform a composite roofing sheet.

14. A roofing element comprising a web of felted fib one materialimpregnated with an asphalt sat ant and carrying on a face thereof acoating of asphalt to form a weather-resisting base sheet forsaidelement, said element having laminated thereto upon a face thereof in anarea underlying at least a portion of the base of an element in the roofassembly a dry web of felted mineral wool fibres in the form of aself-sustain ing felted structure in said dry web and held to said basesheet to form a composite insulated roofing element.

15. A roof comprising shingles arranged in horizontal rows or courses,the butts of the shingles in each row being spaced upwardly from thoseof the next subjacent row of shingles in conventional form. and heatinsulating mats oi inorganic fibrous material having open air-filledinterstices attached to the under surfaces of the shingles, the lengthof said mats being equal to the distance between the butts of adjacentrows of shingles and the width of the mats equal to the width of theshingles. the sides and ends of the mats on adjoining shingles abuttingso as to forma practically continuous, unbroken mat or blanket of saidfibrous material beneath the shingles.

16. A roof comprising shingles arranged in horizontal rows or courses,.the butts of the shingles in each row being spaced upwardly from thoseof the next subiacent row of shingles in conventional form, and heatinsulating mats of inorganic fibrous material having open air-filledinterstices attached to the under surfaces of the shingles, said matsbeing of such size, shape, and position as to abut each other and formin eflect a continuous mat or blanket underlying substantially theentire shingled surface of the roof.

17. The combination of a roofing shingle of greater length than width,and a resilient mat of glass wool having open air-filled interstices,said mat attached to the under surface of the shingle and beingcoextensive in width with the shingle and extendingurom the upper endofthe shingle toward the lower end and terminating at'a pointapproximately midway between the upper and lower ends of the shingle,the size and arrangement of the mat being such that when the shingle isconventionally built into a roof with like shingles, the sides and endsof said 'mat abut those of the adjoining mats on the surroundingshingles so that said mat is completely surrounded by and merged intothe mats of the surrounding shingles to form a practically continuousunbroken mat or blanket of glass wool beneath the shingles.

18. A laminated sheet comprising two layers of mineral wool fibersfelted in each layer to form a web, said layers being bound together toform a unitary laminated sheet, said webs each being formed as aself-sustaining structure containing mineral wool fibers in predominantamount, the felted structure of one of said webs being more open thanthat of the other to provide a substantial insulating quality, the otherweb being feltedto provide a greater strength in the web than that ofthe first web. 1

19. A claim according to claim 18 in which the laminations are feltedtogether to form the unitary structure.

20. A claim according to claim 18 in which the lamination of greaterstrength is impregnated with a bituminous saturant.

ARTHUR DAWEB MAONUT'I.

